The Columbia Pictures film “The Amazing Spider-Man” reaches theaters on July 3, 2012, with a lot of history to live up to — the trilogy of Spider-Man movies directed by Sam Raimi brought in close to $3.5 billion in worldwide box office and keyed billions more in home video, toys, licensing and video games. No one is more aware of that than Marc Webb, the 36-year-old music-video veteran who made his feature directorial debut with “(500) Days of Summer” in 2009 and was the surprise choice to direct this start-from-scratch version of the hero with new star Andrew Garfield. Webb and Garfield begin their conversation with fans on Friday at Comic-Con International, and the filmmaker spoke with our Geoff Boucher about the high stakes.